This past week, the concentration of carbon dioxide in the atmosphere exceeded 400 parts per million (ppm) for the first time in at least 4 million years.

Here’s a simpler, starker way to put it: pollution in the air, the kind that captures greenhouse gases and makes our planet warmer, just reached the highest level ever in recorded history.

The culprit, as scientific research has overwhelmingly demonstrated, is the burning of fossil fuels, a practice that, unfortunately, shows no signs of decline.

Global temperatures will continue to rise and we will see increasingly dangerous climate change in the form of extreme weather events and rising sea levels.

The data couldn’t be clearer. The causes are obvious. The consequences for our children and grandchildren are severe and imminent.

Why then, the lack of urgency for developing clean energy technology and reducing emissions of greenhouse gases? Why isn’t this a priority for our communities, our government and our society?

The answer is simple: Politicians like Virginia Attorney General Ken Cuccinelli.

I’m sure you’re wondering: what in the world does the Virginia Attorney General have to do with any of this?

That’s a great question, one that I probably couldn’t have answered myself until Cuccinelli spent $500,000 in taxpayer money to attack me and the University of Virginia for our climate research. I describe the entire ordeal in my recent book The Hockey Stick and the Climate Wars.

In 2010, Cuccinelli demanded thousands of emails exchanged between me and my colleagues. His authority, he claimed, derived from a state law designed to prevent Medicaid fraud, implying, of course, that our research was made up.

Our climate change research offended Cuccinelli, thanks to his ideology-driven denial of, well, science. Therefore, he used his legal power as Attorney General to orchestrate a witch-hunt meant to smear and discredit me, and by extension, my work.

Lacking any legitimate claim against me, Cuccinelli’s court filing largely ignored actual climate science, but when it was mentioned, Cuccinelli relied on Internet conspiracy theories and disinformation from big oil and coal lobbyists.

Ultimately, though, sanity prevailed and Cuccinelli failed. But now, Cuccinelli’s radical, irrational and fear-based brand of politics has created a template for a like-minded Attorneys General, looking to stamp out opposition by providing a legal basis for attacking environmental rights and voting rights at the state level.

Cuccinelli’s potential successors have actually said the Attorney General has not gone far enough in using the office to promote political extremism. They are basically clones of Ken Cuccinelli, and their victory would mean more attempts to silence opponents and roll back voting rights and environmental protections.

In contrast, Democratic State Senator Mark Herring was the very first elected official to defend me during Cuccinelli’s smear campaign. He showed the kind of integrity and intellectual honesty sorely missing from the Attorney General’s office. And now he’s running for the very same office Cuccinelli abused over the last four years.

Mark’s election would serve as a clear, unequivocal rejection of Cuccinelli’s style of politics and a return to thoughtful, responsible governing. But it would also be a tremendous blow to the political extremists on a national level. Remember, the far right-wing Tea Party planted its roots in Virginia in 2009, which quickly bloomed into a resounding victory in 2010 and dangerous policy from the likes of Cuccinelli in the years since.

When you consider all of these factors, you can quickly see the importance of Virginia’s 2013 elections.

So if you care about climate change…

If you care about governing based on reason and fact…

If you want to stop the political extremists before they can gain their footing once again…

If you believe it’s wrong for law enforcement to try to silence opposition…

Than you should you care about the Virginia Attorney General’s race and you should care about electing Mark Herring.